EIA in the water industry

Janet Langsford and Hannah Kirkham, from MWH, discuss how environmental impact assessment (EIA) is used in the water sector

Water and sewerage projects vary widely in scope and value, but often have some form of environmental benefit as a driver and are sometimes the subject of EIA. The Town and Country Planning (EIA) Regulations 2011, which came into force in August 2011, has introduced changes which may affect a significant number of such projects.

Water industry projects and the planning system

As statutory undertakers, water companies benefit from significant permitted development rights, which enable them to undertake essential maintenance and deal with common below-ground developments. However, with respect to larger or more complex projects, the need for EIAs can arise.

The most common schemes to require EIAs are extensions to existing sewage treatment works, cross-country pipelines for both water supply and sewage treatment, and works involving reservoirs. Other developments that often need EIAs are those that involve innovative technologies, such as advanced digestion plants which use biogas resulting from the digestion of sewage sludge as part of combined heat-and-power systems to generate electricity for on-site use. This technology is becoming more popular with water companies as they seek financial efficiencies as well as environmental benefits.

Along with numerous other types of project on the threshold of Sch.2, it is important to local planning authorities that water companies identify and minimise potential environmental impacts, and much baseline data may need to be collected in the hope of demonstrating no significant effects at the EIA screening stage. For example, for the refurbishment of an urban sewage treatment works in the south of England, the local planning authority requested:

  • a landscape and visual impact assessment, including photomontages;
  • a daylight and overshadowing study;
  • a TV reception study;
  • a traffic statement;
  • a noise assessment;
  • a land quality assessment;
  • an arboricultural survey;
  • landscaping proposals;
  • a flood-risk assessment;
  • a construction environmental management plan; and
  • a detailed odour assessment.

Environmental good practice

Even for projects which are not likely to have significant environmental effects, water companies use effective methods of managing the environmental impacts of their capital projects. A typical approach is to screen projects against comprehensive environmental criteria at an early stage of design, to characterise the development and forecast the likely requirements of consultees, both statutory and non-statutory.

These are essentially mini EIAs, which start at desk-study level and are revisited as the project develops, eventually forming the basis of contract documents and construction environment management plans.

Environmental screening benefits all stakeholders, including the design team, the water company, statutory consultees and the general public. Clear environmental background information from these reports helps engineers to better account for the environment in their designs, which gives confidence to the business and external stakeholders that a solution is robust. It also minimises the risk of re-work, by reducing uncertainty and addressing potential environmental impacts at an early stage.

Potential future changes

As mentioned earlier, projects in the water industry range from small-scale works such as upgrades and maintenance of existing assets that fall below the EIA Regulations threshold, to large projects with need for detailed EIA. However, the 2011 EIA Regulations have increased the potential for more of the smaller projects to require an EIA, due to changes in how extensions to existing installations are treated.

In accordance with Sch.2(13) (changes and extensions), where extensions to existing works are now proposed, the entire development (existing plus extension) must be considered for EIA screening purposes, where previously only the new extensions needed to be considered. This is most likely to affect refurbishments and upgrades to existing sewage treatment works.

In summary

Water companies occasionally embark on projects which require EIA as part of their investment programmes. These projects vary widely and can be contentious, but water and sewerage investment programmes often have environmental drivers at their heart.

While water companies benefit from extensive permitted development rights, and there is a preference to steer projects towards this type of development rather than EIA, in our experience, water companies take a proactive approach to environmental management of projects through screening exercises. This approach allows them to identify the project requirements at an early stage, which then subsequently informs further design and the construction phase.

With the recent update to the EIA Regulations, water companies may need to undertake EIAs more often, as extensions and refurbishments to existing sewage treatment works are likely to come under the EIA threshold.


This article was written as a contribution to the EIA Quality Mark’s commitment to improving EIA practice.

Janet Langsford is a principal environmental planner ([email protected]) and Hannah Kirkham is an environmental scientist ([email protected]), both work at MWH UK.

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